Rotary mechanism having at least two camming elements

ABSTRACT

Rotary mechanisms for fluid power motors or pumps or speed changers which have two or more camming elements. In a 2-element rotary mechanism, one camming element has a simple cam profile and the other has follower rollers. A 3-element mechanism has a third camming element to provide two sets of cam profiles and follower rollers. When used as a fluid pressure device, it is mounted in either of two ways: (a) with each of the three elements on a unique fixed axis or (b) with the outer and inner elements on common fixed axes and the intermediate element floating, its axis orbiting said common axes. For valving the latter arrangement, at least one inboard rotary valve plate turns with the intermediate element, and an outboard, usually stationary, valve plate is attached to the outer element adjacent each rotary plate.

United States Patent [1 1 Grove [4 Oct. 7, 1975 [76] Inventor: Leslie H. Grove, 707 E. Hoyt Ave.,

St. Paul, Minn. 55106 [22] Filed: June 11, 1973 [21] Appl. No.: 368,871

Related U.S. Application Data [63] Continuation-impart of Ser. No. 143,869, May 17, 1971, abandoned, which is a continuation-in-part of Ser. No. 859,117, Sept. 18, 1969, abandoned.

3,490,383 1/1970 Parrett 418/61 B 3,558,245 l/l97l Bolduc 418/61 B 3,591,320 7/1971 Woodling,.. 418/61 B 3,627,454 12/1971 Goff et al. 418/61 B Primary Examiner.lohn J. Vrablik Attorney, Agent, or Firm-David A. Roden; Robert E. Granrud [5 7] ABSTRACT Rotary mechanisms for fluid power motors or pumps or speed changers which have two or more camming elements. In a 2-element rotary mechanism, one camming element has a simple cam profile and the other has follower rollers. A 3-element mechanism has a third camming element to provide two sets of cam profiles and follower rollers. When used as a fluid pressure device, it is mounted in either of two ways: (a) with each of the three elements on a unique fixed axis or (b) with the outer and inner elements on common fixed axes and the intermediate element floating, its axis orbiting said common axes. For valving the latter arrangement, at least one inboard rotary valve plate turns'with the intermediate element, and an outboard, usually stationary, valve plate is attached to the outer element adjacent each rotary plate.

16 Claims, 49 Drawing Figures US. Patent Oct. 7,1975 Sheetlofll 3,910,733

Z24 Z41 2 /Glz 64 Z24,

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628 Z6e 6Z6 US. Patent 6st. 7,1975 SheetZ of 11 3,910,733

US. Patent Oct. 7,1975 Sheet 3 of 11 3,910,733

Fla/0 f2 f6 22 56 i2 F/q. /5c if 1 55.4 lE/7'. GPO vs TQM-1a W r4770R/VEX US. Patent Oct. 7,1975 Sheet 7 0f 11 3,910,733

I NVENTOR.

U.S. Patent Oct. 7,1975 Sheet 8 of 11 3,910,733

l NVEN TOR.

US. Patent Oct. 7,1975 Sheet 9 of 11 3,910,733

I NV ENTOR. 15.52. If hf 6/?0 1/5 BY XMM 2m 4770ENE7 US. Patent 0m. 7,1975 Sheetllofll 3,910,733

ROTARY MECHANISM I-IAVINGAT LEAST TWO.

- CAMMING ELEMENTS Y.

. CROSS-REFERENCE TO RELATED i APPLICATIONS This application is a continuation-in-partof my co'-. pending application S e r.. No. filed May, l7, 1971 now abandoned, which in turn was a continuation-in-part of my application Ser. Nol j8 5 9,l filed Sept. 18, 1969, now abandoned." Those prior applica- 1O tions were directed m three-element rotary mechanisms and to internal pressure devices employing such mechanisms. The secon d-filed application added disclosure concerning rotary valving. The present application extends the disclosure to cover two-element rotary l5 mechanisms and provides further disclosure concerning the method of designing the camming elements of both twoand three-element rotary mechanisms, FIGS. 42, 42A and 42B are added to th e drawing to illustrate the design of a typical three-element rotary rnecha- 20 nism. The first two sheets of drawing'(FIGS. 1 9) are resubmitted in keeping withthe furtl'iei' disclosure and Y to depict more accurately the camming'elements in FIGS. 4-6 and to substitute 'in FIGI'3 a typical two-' element rotary mechanismu l 1. Field of the Invention r This invention relates to. rotary mechanisms having utility as speed changers or as gdisplacement elementsfor internal pressure devices such as fluid power motors, pumps, actuators,-and power steering units and to improved valving means for ingress and egress ,of fluid from the expandingand .collapsing inner; and outer chambers of pumps,,and motors-employing multipleelement rotary mechanisms.

2. The PriorkArt i I h 35 and 2,01 1,338 (No/Re. '2 l,3l6)-'and the books "Kine matics of Gerotors," by Hill, 1927, and Kinematics of Gerotors, Rotoi'cls and Gears, by Hill, 1947. i

In the early and manyco'ntempora'ry commercial intemul gear motors and pumps, the axis of the i'ri'ternalgear and the axis of the external gea'r are fixed-but not common; thus both the inner and outer gears rotate on parallel but separate axes. 1

An important advance in the art is shownin Charlson U.S.- Pat. No. 2,821,171 in which one'gear is stationary and the other gear orbits about the axis of the stationary gear, the axis of the orbiting gear taking a substantially circular path'about the axis 'of. the stationary gear. This arrangement allows a gear reduction within the unit, thereby providingamincreased volumetric displacement, and thus ahigher shaft torque for the same size gear set as used in the above-mentioned fixed axes motors. A disadvantage, however, of many of thezmotors in which the inner gearorbits is the fact thatthe linkage between the innergear and the output shaft is provided by one or more wobble'shafts which act as.

this portion of the device.

, element may be formed on a tracing lathe ora magnetuniversal joints. Frequent breakage is expei'iencedwjth I Internal gearsets having three concentric gears or elements also are known in the art,e.g. see Feuerheerd US. Pat. No. 1,389,189 which uses elements having a circular tooth fomr,'Sanson U.S. Pat. No. 3,217,566

and Eddy US. Pat. Nos.,.3,453,966 and 3,456,559

which employ elements having a gerotor or generated tooth-form. In the Feuerheerd and Sanson devices each gear or element rotates on its own fixed'axis; in the Eddy devices the inner and outer gears have a common I fixed axis, and the axis of the intermediate gear travels v in a substantially circular orbit about the axis of the other gears.

Although the internal gear sets-of the prior art provideeffective and .efficient rotary mechanisms, the gears are, difficult to design and to machine and the THE PRESENT INVENTION The rotary mechanism ,of the present invention provides economy and versatility by employing camming elements which are easilyformed and duplicated and which experience very little wear in use. When used as a fluid pressure device, the novel rotary mechanism inherently provides a positive fluid seal between adjacent chambers. In its simplest form, the novel rotary mecha nism has two camming elements, the second having its inner fact in contact with the outer face. of the first camming element. One of those faces has a cam profile of at least three identical segments, each segment including a firstaxi'ally-straight, radially-circular surface connected to the corresponding first surface of the adjacent segmentby a second radially-circular surface of a different radiuswhich is tangent to the first surfaces. The radius-of either of the first or second circular surface maybe infinity, in which case that surface is flat. Theother of, the contactingpair of faces has at least three equallyspaced follower rollers in slightly oversize U-shaped sockets permitting radial movement of the rollers, which sockets are connected by a surface which does not interfere with the cam profile upon relative rotation of the camming elements. The number ofrollers differs by at least one frornthenumber of camsegments. Each roller is in contact with the cam profile during rotation of one camming element relative to the other,

In, a specific two-elementrotary mechanism of the present invention, the first camming element may have a cam profile of nidentical lobes, and the second camming element may have m identical axially-straight,

radially-circularconcave surfaces terminating at m U- shaped sockets, m and n being differing integers, each at 'least '3. In order to provide a positive fluid seal when the rotary mechanism is used as a fluid pressure device, the maximum breadth across the lobes of the first camming element should equal the spacing between any of the follower rollers and thernost distantjconcave surface while the roller is still free to move. radiallyin its oversize socket, .Toconstruct this specific two-element rotary mechanism,' the outer face of the first camming i c-tape-controlledmilling machine, followed by grinding on a conventional cam grinder. The inner face of the second camming element may be formed by drilling holes to receive the follower rollers and by drilling or milling a hole or holes to provide'the concave surfaces between the rollers.

In operation, rotation of one camming element while the other is stationary, causes the axis of the rotating element to orbit about the axis of the stationary camming element.

A three-element rotary mechanism of the present invention adds a third or outer camming element to the first or inner camming element and the second or intermediate camming element of the basic two-element mechanism. The inner and intermediate camming elements are constructed in the manner described above for the two-element rotary mechanism. In the threeelement mechanism, the intermediate camming element has its outer face in contact with the inner face of the outer camming element and its inner face in contact with the outer face of the inner camming element. At each contacting pair of faces, there is one cam profile and one set of rollers as in the two-element rotary mechanism. There is no limitation in the relationship of numbers of rollers and segments in the cam profile at one contacting pair of faces to the numbers at the other pair of faces. However, for use as an internal pressure device, the configuration of the porting in the valve plates is simplified if there is a difference of 2 between the number of face segments or rollers at the outer face of the inner camming element and the number at the inner face of the outer camming element. When a difference exists, the larger number may be on either the inner or the outer camming element, but for simplified porting, the larger number is preferably on the outer camming element. Moreover, for ease of designing and machining, it is usually preferred that the difference between the number of rollers and contacting segments of the cam profile be either one or two.

The novel three-element rotary mechanism permits the use of a straight shaft instead of the aforementioned wobble shafts, whereby a common source of mechanical failure in certain high displacement prior art motors is avoided. The inner camming element may be easily formed as an integral part of the shaft, thereby eliminating the need for keying or splining of the element to the shaft and thus providing greater strength.

If desired, a fourth or more camming elements may be added concentrically around the three-element rotary mechanism, for example, to effect further volumetric displacement and to increase output torque, or

to mix or pump more than two fluids at one time. In any case, the displacement height of every cam profile is equal.

The simultaneous pumping of two fluids is particularly useful where metering and subsequent mixing of the fluids is desired, for example, with an epoxy resin and a hardener therefor, or water and a soap solution.

The rotary mechanisms of this invention permit one to achieve greater volumetric displacement as compared to prior art internal gear type rotary mechanisms having the same envelope size, i.e., the same limiting dimensions, and therefore the elements of this invention may provide greater torque per unit size.

The sequence valving for motors and pumps employing three-element rotary mechanisms wherein the inner and outer elements are mounted on a common fixed axis, consists of at least one inboard rotary plate which is arranged to turn with the intermediate element, e.g.,

with the drawings, either the inner or outer element may be held fixed to prevent rotation thereof.

THE DRAWING The present invention is further illustrated in the accompanying drawings in which like parts have like numbers.

FIG. 1 is a plan view of a three-element rotary mechanism according to the invention;

FIG. 2, is a section along line 22 of FIG. 1;

FIG. 3 is a schematic plan view of a two-element rotary mechanism of the present invention;

FIG. 3a is a section along line 3a3a of FIG. 3;

FIGS. 4, 5 and 6 are plan views of additional three-v element rotary mechanisms according to the invention;

FIG. 7 is an illustrative displacement curve diagram representative of the camming action of the threeelement rotary mechanisms.

FIGS. 8 and 9 are, respectively, an end view and a side elevation of a shaft on which the inner camming element of a rotary mechanism of the invention has been formed as an integral part thereof for use in a motor or pump;

FIG. 10 is a section of a fluid-powered motor according to the invention taken along line 10-10 of FIG. 11 and utilizing a pair of rotary inboard valve assemblies such as that shown in FIG. 12 and a pair of stationary outboard valve plates such as that shown in FIG. 15;

FIG. 11 is a plan view of a 3-element rotary mechanism use in the motor of FIG. 10;

FIG. 12 is a plan view of a rotary valve assembly used in the motor of FIG. 10;

FIG. 12a is a section along the line l2a-12a of FIG. 12;

FIG. 13 is a plan view of a' variable volume control plate which may be employed in motors and pumps ac cording to the invention;

FIG. 14 is a section along the line l414 of FIG. 13;

FIG. 15 is a plan view of a stationary valve plate used in the motor of FIG. 10;

FIG. 15a is a section along the line 15a-l5a of FIG. 15;

FIG. 15b is a plan view of the stationary valve plate which may be used in the motor of FIG. 18;

FIG. is a section along the line 15cl5c of FIG. 15b;

FIG. 16 is a section of a modification of the motor of FIG. 10 in which the motor is ported through both ends of the shaft;

FIG. 17 is a section of a modification of the motor of FIG. 16, which is ported from one end of the shaft only;

FIG. 18 is'a section of a modification of the motor of FIG. 17 in which only one rotary valve plate and one stationary valve plate is used;

FIG. 19 is a central section of the stationary valve plate of the motor of FIG. 16;

FIG. 19a is a central section of the stationary valve plate of the motor of FIG. 18;

FIG. is a section of a pump according to the invention taken along the lines 20"20 of FIG. 29 and'employing the rotary mechanism of FIG. 4;

FIG. 21 is a plan view'of a porting plate used in the pump of FIG. 20;

FIGS. 22, 23, 24 and 25 are plan views of alternate forms of channel plates useable in the pump of FIG. 20;

FIGS. 26, 27 and 28 are plan views of alternate forms of end plates'for usein making alternate forms of the pump of FIG. 20;

FIG. 29 is a side elevation of the pump of FIG. 20 attached to an electric motor;

FIG. 30 is a section of another pump employing the three-element rotary mechanism of FIG. 4 and taken along the lines 3030 of FIGS. 31, 32, 33 and 34;

FIG. 31 is a plan view of an end plate used in the pumps of FIGS. 30 and 41;

FIG. 32 is a plan view of a port plate used in the pumps of FIGS. 30 and 41;

FIG. 33 is a plan view of an outlet manifold used in the pump of FIG. 30;

FIG. 34 is a plan view of an inlet manifold used in the pump of FIG. 30;

FIG. 35 is a plan viewof a cross-over manifold used in a modification of the pump of FIG. 30;

FIG. 36 is a plan view of a cross-over manifold used in another modification of the pump of FIG. 30;

FIG. 37 is a plan view of an outlet manifold for one fluid used in the two-fluid pump of FIG. 41;

FIG. 38 is a plan view of an inlet manifold for one fluid used in the two-fluid pump of FIG. 41;

FIG. 39 is a plan view of another inlet manifold for the second fluid used in the pump of FIG. 41;

FIG. 40 is a plan view of an outlet manifold for the second fluid used in the pump of FIG. 41;

FIG. 41 is a section of a two-fluid pump employing the three-element rotary mechanism of FIG. 4 and taken along the lines 30-30 of FIGS. 31, 32 and lines 41-41 of FIGS. 37, 38, 39 and 40; and

FIGS. 42, 42A and 42B illustrate the design of the rotary mechanism of FIG. 11 and may be considered of common geometric design separated into three parts.

Because many vehicles employ engines that have crankshaft speeds of about 7,000 rpm, fluid pumps mounted directly to the crankshaft and turning at these high speeds often experience failure of the fluid seals. Therefore it is common practice to employ some type of speed reducer for lowering the speed at which the hydraulic pump will operate. The two-element rotary mechanism 10 shown in FIG. 3 provides built-in speed reduction which permits it to be operated as a fluid pump at an input shaft speed of about 7,000 rpm. The outer face of its first camming element 12 has a cam profile of five identical segments or lobes, each formed by a first axially-straight, radially-circular convex surface connected to each adjacent convex surface by a second radially-circular concave surface of a different radius which is tangent to the convex surfaces.

The inner face of the second camming element 13 includes three follower rollers 14, each located in an oversize U-shaped socket 15 permitting free radial movement. The sockets 15 are connected by three identical axially-straight, radially-circular concave surfaces which have a common center.

The first camming element 12 is mounted on the central eccentric 16 of a crankshaft 17 (FIG. 3a) by a needle bearing 18. A specific pump has been constructed of the following materials:

First element 12 Second element l3 Rollers l4 Crankshaft l7 Needle bearing 18 One revolution of the crankshaft 17 produces one-fifth revolution of the first camming element 12. At a crankshaft rotation of 7,000 rpm, the first element 12 rotates well within the capacity of conventional fluid seals.

Rotation of the first camming element 12 in a clockwise direction from the positions shown creates higher pressure at the right side of the roller 14 shown at the top of FIG. 3. This forces the roller against the left side of its socket 15. Inasmuch as the socket is oversize to permit free radial movement of the roller, the higher fluid pressure extends across the top of the roller as compared to its lower left side, thus forcing the roller against the camming element 12. This motion of the roller in the oversize U-shaped socket occurs in all the devices of FIGS. 1 to 428.

If the rotary mechanism 10 were used as a motor, fluid flowing into that portion of the chambers 19 to the left of the top roller (causing clockwise rotation of the inner camming element 12) would force the roller against the right side of the socket and inwardly against the camming element 12, likewise insuring contact between the roller and the cam profile.

If the rollers were on the outer face of the inner camming element and the inner face of the outer camming element had a cam profile, the rollers would be forced by the fluid outwardly against the cam profile, both in pump and motor use.

A typical three-element rotary mechanism 20 of the present invention is shown in FIG. 11. The outer face 28 of the first or inner camming element 26 has a cam profile of three identical lobes. The inner face 37 of the second or intermediate camming element 24 has four axially-straight, radially-circular surfaces, each of approximately the radius of the lobes of the outer face 28, which surfaces terminate at four oversize U-shaped sockets, each containing a follower roller 40. The outer face 36 of the intermediate camming element 24 has an outer facing cam profile of four identical lobes. The inner face 38 of the third or outer camming element 22 has five axially-straight, radially-circular surfaces, each of approximately the radius of the lobes of the face 36, which surfaces terminate at five oversize U-shaped sockets, each containing a follower roller 41.

For purposes of illustration, the design of the rotary mechanism shown in FIG. 11 will now be explained with reference to FIGS. 42, 42A and 42B which should be considered as a single figure of common geometric construction separated into three parts for purposes of clarity.

1. Referring to FIG. 42, locate points B on the 45, 225 and 315 polar coordinates at a polar distance about 2 to 3 times the diameter of the intermediate portion 64 (FIG. ll) of the shaft.

2. With each point B as a center, construct circles A at the radius of the rollers 40 (FIG. 11

3. On the Y axis, establish point C equal to or somewhat closer (as shown) to the center point 0 that is the line between the points B on the 45 and 135 polar coordinates.

4. From point C, draw lines at 30 angles to the Y axis and intersecting circles A at points C.

5. With point C as a center point, find the smaller radius R that will provide a circle tangent to circles A on the 45 and 135 coordinates, and establish points C on lines CC so that the distance C'C" equals R which is the radius of each of the three lobes of the inner camming element 26 (FIG. 11).

6. From points C draw lines at 60 to the Y axis and intersecting the Y axis at Distance 00 equals 1/2H of FIG. 7.

7. Referring to FIG. 42A, swing arcs D from centers C and C" with radius R.

8. On each extended line OC and OC at a distance from the intersection of the line with an are D equal to the diagonal distance between circles A of FIG. 42, locate point E.

9. Through points E swing arcs that are tangent to arcs D, which arcs together define the cam profile 28 of the inner camming element 26.

10. Referring to FIG. 42B, on the 54, 126, 198, 270 and 342 polar coordinates locate points F at a polar distance somewhat larger than 3R and construct circles G G G G and G respectively, from center points F having the radius of the rollers 41 (FIG. 11).

l 1. Locate point J on the 90 polar coordinate at a dstance equal to the distance from O to the circle G H.

12. Locate the center point K of the line O'.} and with K as the center swing an are L (dotted line) that passes through point J and is tangent to circles G and G 13. ()n the 45 polar coordinate, locate a point M at a distance from circle G equal to the radius K].

14. Referring back to FIG. 42, on the 135, 225 and 315 coordinates locate points M at the polar distance OM.

15. Draw arcs N from centers M and M at radii equal to KJ.

16. On the X and Y axes, set points P at a polar distance equal to the polar distance of circle G (FIG. 42B).

17. Through points P swing arcs that are tangent to arcs N, which arcs together define the cam profile 36 of the intermediate camming element 24 (FIG. 11).

18. On the X and Y axes, from centers at a polar distance equal to OC, draw arcs Q using a radius slightly larger than R. The arcs O, which provide the lobereceiving surfaces of the inner face 37 of the intermediate camming element 24, terminate at oversize U- shaped sockets S which are sufficiently large to permit free radial movement of the follower rollers 40 indicated by circles A.

19. Referring to FIG. 428, on extended lines OF locate points K at a distance from 0 equal to O'K; from points K and K swing arcs T with a radius slightly larger than KJ terminating at oversize U-shaped sockets which allow for free radial movement of the follower rollers 41 indicated by the circles G The arcs T designate the lobe-receiving surfaces of the inner face 38 of the outer camming element 22.

The lobe-receiving surfaces of the inner faces of both the outer camming element 22 and the intermediate camming element 24 have slightly larger radii (as indicated above) and/or slightly radially-outward centers as compared to the lobes they receive in order to provide mechanical clearance.

In the rotary mechanism shown in FTG. 11, the inner follower rollers 40 and the lobes of the cam profile 36 of the intermediate camming element 24 are on the same polar coordinates. Accordingly, the fully expanded chamber of the inner chambers 44 is from the fully expanded chamber of the outer chambers 42 which is desirable for use as an internal pressure device. When the outer camming element 22 is stationary, each 48 of rotation of the inner camming element 26 provides a new pair of fully expanded chambers 180 apart. For each complete revolution of the inner camming element 26, the intermediate camming element 24 rotates 144 and a pair of chambers will be fully expanded 7 /2 times. Clockwise rotation of the inner camming element produces counterclockwise order of expansion of the chambers.

If the inner camming element 26 is stationary, clockwise rotation of the outer camming element 22 produces clockwise order of expansion of the chambers.

If desired, the inner follower rollers 40 can be offset up to 45 with respect to the polar coordinates of the lobes of the intermediate camming element 24. At 45, there is the greatest possible lag between fully expanded inner and outer chambers, which is advantageous for speed-changing use.

FIGS. 1 and 4-6 each show a three-element rotary mechanism which is numbered similarly to that of FIG. 11. In FIG. 1, the inner follower rollers 40a are part of the inner face 37a of the intermediate camming element 24a, and the outer follower rollers 41a are part of the outer face 36a of the intermediate camming element. The inner camming element 26a is formed with a bore 32- and a keyway 34. Alternatively, the inner camming element can be, and preferably is, formed as an integral part of a shaft, as is the camming element 26e on the shaft 62a shown in FIGS. 8 and 9.

In FIG. 4, both the inner follower rollers 40b and the outer follower rollers 41b are part of the faces of the intermediate camming element 24b.

In FIG. 5, the inner follower rollers 400 are part of the outer face 280 of the inner camming elements 26c, and the outer follower rollers 41c are part of the outer face 366 of the intermediate camming element 24c.

In FIG. 6, the inner follower rollers 40d are part of the outer face 28d of the inner camming element 26d, and the outer follower rollers 41d are part of the inner face 38d of the outer camming element 22d. The inner and intermediate camming elements of FIGS. 5 and 6 by themselves provide identical two-element rotary mechanisms of the present invention; as do the intermediate and outer camming elements by themselves of FIGS. 4 and 5.

In each of the rotary mechanisms of FIGS. 1, 5, 6 and 1 1, the inner and outer camming elements have a common axis, and the axis of the intermediate camming element is offset therefrom. For effective pumping or motor action, either the inner or outer camming element should be stationary while the other rotates.

FIG. 7 illustrates in the upper portion a displacement curve representative of the camming action between the outer and intermediate camming elements of the rotary mechanisms of each of FIGS. 11, 5, 6 and 11; and in the lower portion a displacement curve representative of the camming action between the inner and intermediate camming elements. Each curve has the same height H equaling the difference between the minimum and maximum radii of each camproflle In the rotary mechanism of. FIG. 4, each of these camming elements rotates on a fixed axis with the axis of the intermediate camming element 24b offset adistanc e above the axis of theinner camming element 26b and the same distance below the axis of the outer camming element 22b. This arrangement permits simplified pump or motor construction and is'useful where lower pressure operation is desired whereas the rotary mechanisms of FIGS. l, 5,6 and 11 generate much higher pressures.

FIG illustrates a novel hydraulic motor 50 employing the rotary mechanism illustratedin FIG. 11. The motor 50 has a housing 52 comprising substantially identical end sections 54 and'54', substantially identical stationary outboardvalve plates 72 and 72; and between each outboard valve plate and the novel displacement element, identical inboard rotary valve assemblies 56 and 56'. The end sections, the outer rings of the rotary valve assemblies, and the outer camming element 22 of the rotary mechanism are rigidly held together in axial alignment by circumferentially spaced bolts 58 which extend through aligned bolt holes 60 thereof. A rotary shaft 62 extends axially through the motor, and as can be seen from 'FIGS. .10, 11 and l61'8, the inner camming element 26 has been formed as an integral part of the shaft62. pThe shaft 62 has two intermediate portions 64.and 64'-which are of greater diameter than the end portions 66 and 66. Thrust bearings 68 and 68 are positioned around the most medial part of the end portions of the shaft, between an. inner face of the end sections 54, 54 and the external faces of the enlarged intermediate shaft portions 64'and 64' respectively. These thrust bearings help maintain axial alignemnt; of the inner camming element within the motor so:that.;wearing of the stationary valve plates 72, 72 fromfany axial thrust on. the shaft (due to such things as internal fluid pressure between parts or external axial loads against the shaft) is minimized. Ball bearings 70,70 are provided around each end of the shaft where it passes through the end sections 54, 54. These bearings aid in maintaining shaft alignment under radial (side) loading.

Identical rotary valve assemblies 56, 56 are .positioned respectively between the stationary valve plates 72, 72 and the rotary mechanism 20. As shown in FIG. 12, the rotary valve a.ssembly,56 has an outer stationary ring 59, an-outer rotatableeccentric ring 57in sliding engagementwithin ring 59, a rotatable .plate 53 which has holes 73 forbolting the plate to the intermediate camming element 24 and a plurality ofinner ports 86 and outer ports 84 thorugh the plate; and an inner eccentric ring 55 which is sized to be in sliding engagement with the plate 53 on its outer circumference and the intermediate portion 64 on its inner circumference. As can be-seen in FIG. 12a, the eccentric rings 57. and

55 have, respectively, inwardly .and outwardly extending lips 51 which form step shouldersthereon, and the rotating plate 53 is. shaped with corresponding shoulders sothatouterward pressure against the medialaspect of the plate forces the edges of the shoulders into sealing engagement with the lips 51.

The stationary valve plates 72, 72 also have a number of fluid passageways 76, 76 whichare in continuous communication with a circumferential groove 80, 80 that is'formed-in each valve plate. The grooves 8O and are in alignment and constant communication with fluid ports 82 and 82' through openings 83 and Thrust rings 100, and 100 are urged against the exterior faces of the stationary valve plates 72 and 72 respectively by spring means 102 and 102 which are placed in pocketsl04 and 104 in the end sections 54 and 54. The resiliently .held thrust rings maintain sealing engagementbetween the stationary valve plates 7 2, 72 and the rotating parts of the rotary valve assembly 56, 56. The urging of the spring means should be sufficient to overcome the exteriorly directed axial thrust created by the fluid pressure as the fluid presses against the exterior face of the rotary valve assembly 56 (and 56') through the hereinafter described ports 88 and of the stationary valve 72 while these ports are out of communication with ports 84 and 86 of rotary valve assembly 56.

In operation of the motor 50, fluid enters the expanding chambers and leaves the collapsing chambers through appropriately placed ports in the rotary valve assembly 56 and 56.

The rotary valve plates 53 and 53' are provided with outer ports 84 and inner ports 86. The number of outer ports and the number of inner ports are each respectively equal in number to the number of segments on the outer face 36 and the number of rollers 40 on the inner face 37 of the intermediate camming element 24. The outer ports are positioned equidistantly apart from each other and also are each the same distance from the center of plate 53. The inner ports are likewise positioned equidistantly apart and an identical distance from the center of plate 53. At least one inner'port 86 and one outer port 84 are centered on the same radial line. The distance from the center of plate 53 to the medial, -or inner edge of the outer ports 84 is equal to or slightly longer than the radial distance from the center of the intermediate camming element 24 to the midpoint between two crown points on its outer face. The radius to the distal or outermost edge of the inner ports 86 is equal to or slightly less than the radial distance from the center of the intermediate camming element 24 to the midpoint between two rollers on its inner face.

As is understood by those skilled in the art, the total area of a given port or port set should be sufficient to allow enough fluid to pass therethrough to completely fill an expanded chamber during the dwell time when that particular port is receiving fluid from a port of the stationary valve plate 72 of FIG. 15. (As used herein, dwell time refers to the total time that a port of the valave rotor is in communication with a port of the stationary valve plate.)

The plate 72 has outer ports 88, the number thereof being one more than the number of outer ports 84 in the rotary plate 53. ,Plate 72 also has inner ports 90, the number thereof being one more than the number of inner ports 86 of plate 53. Onev of the ports 88 and one of the ports 90 are on the same diametrical line, positioned l80 apart. Ports 88 are of a size and so positioned in plate 72 so that as plate 53 rotates communication is maintained between a port 88, a port 84 and a chamber 42 during complete expansion of that chamber (and on the discharge side communication is maintained between a port 88", a port 84 and a chamber 42 during collapse of that chamber). Inner ports 90 are likewise positioned and adapted to, maintain communication with a port 86 and a chamber 44 during expansion of that inner chamber (and communication is similarly maintained between a port 90, a port 86 and a chamber 44 during collapse of that inner chamber).

As illustrated in FIG. 15, is is presently preferred to shape the radially outermost edges of ports 88 and 90 so that their edges correspond respectively to the curvature of the lobes of the outer faces 36 and 28, respectively of the intermediate and inner camming elements. Stationary plates 72, 72' are prevented from rotating with the motor by dowel pins 74 which are placed in the recesses 77 in plates 72, 72 and in sections 54, 54. Proper timing of the motor is provided by arranging the parts of the rotary mechanism as shown in FIG. 11 and then positioning and fastening the plates 53 and 53 to the intermediate camming element 24, e.g., by putting bolts or other fastening means through the matched holes 73. In so doing, each outer port 84 and its medially adjacent inner port 86 should be positioned, one on either side of the midpoint of the face segment between two lobes on the outer face 36 of the intermediate camming element 24. Next, stationary valve plate 72 is positioned within the motor so that an outer port 88 thereof is almost in communication with an outer port 84 of plate 53, which port 84 is in communication with a fully expanded chamber 42. A like positioning is made with the plate 72 on the other side of the rotary mechanism except that the port 88 is positioned to the opposite side of port 84 as compared to the relative positions of ports 88 and 84. In other words, if when looking towards the rotary mechanism from one end of the motor, the port 88 is just clockwise from port 84, then port 88 should be positioned just counterclockwise from port 84', when viewed from the same end of the motor.

Plates 72 and 72' are used as above described in the motors of FIGS. 10, 16 and 17 when the shaft 62 turns and the motor case 52 is stationary.

In operation, fluid is channeled to chambers which are expanding and collapsing sequentially in a direction of rotation opposite to the rotation direction of the shaft.

In FIG. 1 1, the fully expanded outer chamber 42 and the fully expanded inner chamber 44 are 180 out of phase. As fluid is forced into the expanding chambers, the intermediate camming element 24 is forced to rotate, and in so doing causes the shaft 62 to rotate. As the intermediate camming element rotates, the valve plate 53 also turns bringing into communication a new set of ports 88-84 and 90-86 whereby another set of expanding chambers is forced open by the fluid thereby causing continuous rotation of the shaft. At the same time a new set of collapsing chambers is brought into communication on the discharge side. Thus, as fluid enters the motor via fluid inlet 82 it passes into and fills circumferential groove 80 in the stationary valve plate 72. Some of the fluid then passes through the fluid passageways 76 and enters the stationary valve plate inner ports 90. More of the fluid passes from the circumferential groove 80 through the outer ports 88.

In the arrangementjust described, maximum possible output torque from that particular motor may be achieved.

The output torque may be expressed by the formula T D X 0.l59 psi where T torque in pound inches and D volumetric displacement in cubic inches/shaft revolution and psi is fluid pressure in pounds/sq.in.

Therefore, changing the volumetric displacement will change the output torque.

Application of the just described principle is shown in the motor 50 of FIG. 10 which may be converted to a variable displacement motor by inserting the variable position valve assembly 156 of FIG. 13 between stationary valve plate 72 and rotary valve assembly 56. The assembly 156 has an outer ring 92 surrounding a movable valve plate 96 which contains ports identical in size to those present in plate 56 of FIG. 12. These port locations have the same mean average radii and location as the ports 88 and 90 of the stationary valve plate 72. Preferably the ring 92 has a shoulder 94 and the plate has a cooperating lip 95 whereby the plate lip may be held flush against the ring on one side and the plate is held flush against the rotary valve plate on the other side. Positioning means 98, which is here illustrated as a hand-moved lever, but which could be connected to automatic controls of any suitable nature, is attached to the plate 96 and allows one to change the position of the ports 84" and 86" in relation to the rotary valve plate 53, so that the ports 84" and 86" are phased out of communication with stationary ports 88 and 90 before the chambers in the displacement ele* ment are fully expanded. This reduces the volumetric displacement per shaft revolution and thus reduces the output torque. It should be noted that the position of the discharge valve plate 56 is not changed, so that the collapsing chambers are able to substantially empty.

If a bi-directional motor is desired, a second variable position valve assembly 156 can be inserted between stationary valve plate 72 and rotary valve assembly 56 in a motor of the type illustrated in FIG. 10. However, the plate 156 which is on the discharge side of the motor is always positioned so that the appropriate ports 84 and 86 fully communicate with the corresponding fully collapsed chambers 44 and 42 respectively.

Referring now to FIGS. 16 and 17, motors and 250 are substantially like motor 50 of FIG. 10 except that these motors are ported through their shafts. The modifications are as follows. In place of the stationary valve plates 72 and 72 peripherally closed stationary valve plates 172 and 172 of.FIG. 19 are used which have an interior circular fluid groove or 180 respectively.

The stationary shaft 162 in motor 150 has at least one fluid port 182 and 182 entering the shaft beyond the respective end sections 54, 54' which ports communicate with axial fluid passageways 181, 181 respectively. Each passageway terminates in at least one radially extending channel 183 or 183' which in turn communicates with the interior circular fluid groove 180, 180 in the stationary valve plates 172, 172'. The diameter of the passageways 181, 181 will be governed by the fluid flow desired for the motor, in conjunction with consideration of the shaft diameter in relationship to the load it must bear. For example, a /2 inch diameter passageway 181 could terminate in four radially spaced A; inch channels 183, if desired.

In motor 250, the stationary shaft 262 is ported from one end thereof, the fluid ports 282, 282 entering the shaft beyond the end section 54'. The ports communicate with axial passageways 281, 281 respectively, which in turn terminate in channels 283, 283' leading into the internal grooves 180, 180'.

In operation, the shaft of motors 150 and 250 is held stationary and fluid flowing into the expanding and collapsing chambers of the rotary mechanism 20 causes rotation of the housing 52. By inserting assembly 156 of FIG. 13 between assembly 56 and the stationary valve plate l72, the motor maybe used as a"hydro static wheel hub, i.e. thehub has variable'specd and torque even though the fluid supplied to the hub motor is at a constant pressure and volume.

FIG. 18 illustrates a motor'350 having a potentially shorter axial length housing than the just described motors by dint of the fact that the two stationary valves 172 and 172 have been replaced by a single unitary stationary valve 372 as shown'in FIG. 19a. In motor 350 one assembly 56 has been replaced by a wear plate 385; The bell-shaped end section 54 is replaced by a slightly different shaped end section 354.

I The unitary stationary valve 372 of FIGS. 18 and 19a has radially spaced outer ports numbered 388B and in FIG. 19a, and also has similarly designated inner ports 390E. The valve has two separate circular passageways 380 and 380'. Every other outer port and every other inner port connects to one passageway, and the alternate ports connect to the second passageway.

Shaft 362 of FIG. 18 is similar to shaft 262 of FIG. 17, the inner camming element 26 being formed integrally therewith. However, whereas the variable sequence valve assemblyl56 of FIG. 13 may be used in the motors of FIGS. 16 and 17, it cannot be used in its illustrated form in the motor of FIG. 18. Thus motor 350 is a flxed displacement motor, and is primarily designed for use where the axial space is a limiting factor, with the shaft stationary and the housing rotating. With stationary shafts, motors 150, 250 and 350' lend themselves for use as wheel hubs for automobiles, trucks, tractors, farm machinery and equipment, off-highway construction equipment, winches and many other similar uses.

If one desires to hold the housing of motor 350 stationary and rotate the shaft, rotary manifolds or unions are provided in known manner over fluid ports 382, 382. The unitary stationary valve 2720f FIG. b may replace the unitary valve plate 372 of FIG. 19a. Valve 272 may be used in place of valve plates 72, 72 and one valve assembly 56 in any of the motors of FIGS. 10,.

I6 and 17 if one desires to shorten the axial length of those motors. The stationary valve plate 272 of FIG. 15]; is generally similar in arrangement and function as the above described plate 372 of FIG. 19a.

The valving for the hydraulic motors of FIGS. 10 and 16-18 requires the inner and outer camming elements to have a common axis, as in the rotary mechanisms of FIGS. 1, 5, 6 and 11. Because-the inner and outer camming elements of the rotary mechanism of FIG. 4 have spaced axes, different valving is required, as in the pumps of FIGS. 20, 30 and 41 discussed below.

FIG. 20 shows a pump 450 cut along the lines 2020 of FIG. 29 and 20-20 of FIG. 4. The pump has a shaft 462 passing through the end section 454, with the inner camming element 26]) of the rotary mechanism 201) being formed as an integral part of the shaft. A porting plate 456 as shown in FIG. 21 is held against the rotary mechanism on the side opposite the shaft and forms one axial end of the expanding and collapsing chambers, the other axial end of the chamber being closed by the end section 454.

The porting plate 456 has a pair of opposed kidneyshaped semi-circular inner ports 486, 486"v and opposed outer ports 484, 484. The size and shape of the ports is selected in accordance with known design practices to allow for complete filling of the expanding chambers without cavitation. The inner and outer ports on one side of plate 456 will be on the suction side of the pump (i.e. communicating with expanding chambers) and the ports on the other side will allow fluid to pass from the collapsing chambers to the discharge port of the pump.

A channel plate 472 as shown in FIG. 22 is held in fixed position against the porting plate 456 by an end plate 455 and by bolts 458 which pass through bolt holes 460, the latter being provided in each of the individual parts of the pump except the shaft and the units of the displacement element 20, for in this pump all of the units of the displacement element rotate.

The plate 455 has at least two ports 482 and 482 f0 connection with suction and discharge lines.

Pump 450 can function as a single fluid pump, a twofluid pump, as a two-stage or compound pump, or as a mixing pump (by accepting two fluids and discharging these fluids through a single port). This device may also function as a rotary intensifier for increasing fluid pres sure, or as a high speed, low torque fluid motor. These and other variations are achieved by appropriate design of the channel plate 472 and the end plate 455, and the conditions under which the device is operated, i.e. power input via the shaft, or via fluid pressure through the inlet port.

All three camming elements of the rotary mechanism 20b turn, and at different speeds. Since the inner camming element 26b has three face segments, and the inner face 37b of the intermediate camming element 241) has four rollers, the element 2412 will turn threefourths of a revolution for each complete revolution of the inner element 26b. For each revolution of the intermediate element 24b, the outer camming element 22b will turn four-fifths of a revolution. Therefore the other element will turn three-fifths of a revolution for each complete revolution of the inner element. The reduction ratio will be altered, of course, by changing the number of face segments or rollers on the opposed faces of any contacting camming elements. Thus a wide variation in speed, displacement and volumetric capacity may be designed into the motors, pumps, hydrostatic drives and rotary intensifiers utilizing the rotary mechanism of the present invention.

As illustrated in FIG. 20 the pump 450 utilizes the porting plate 456 of FIG. 21, the channel plate 472 of FIG. 22, and the end plate 455 of FIG. 26, and will function as a single fluid pump by rotating shaft 462 to cause suction of fluid into the expanding inner and outer chambers via fluid port 482 through channel 471 in channel plate 472, and through inner and outer kidney ports 484 and 486. The fluid then leaves the collapsing inner and outer chambers via inner and outer kidney ports 484 and 486, through channel 471 and fluid port 482.

To change pump 450 to a two-stage pump, one need only substitute therein channel plate 472A of FIG. 23. Fluid entering via port 482 passes through channel 471A into kidney port 486 and into the inner chamber 44}; while it is expanding. Fluid is discharged from the inner chamber 441) while it is collapsing into kidney port 486, to channel 471A" into kidney port 484 whence it flows into the expanding outer chambers 42b. From the collapsing outer chambers it is forced into kidney port 484 to channel 471A and thence out through fluid port 482.

To provide a mixing pump which takes in fluid from two sources (e.g. so that two different fluids such as water and liquid soap may be mixed), and discharges them through one outlet, the channel plate 4728 of FIG. 24 and the end plate 455A of FIG. 27 may be employed. As illustrated, the inlet for one fluid is through port 482 of plate 455A and the inlet for the other fluid is through port 482". In operation one fluid passes from port 482 into channel 4718' and through kidney port 486 into expanding inner chambers 44b. The other fluid entering through port 482" flows through channel 471B" and through kidney port 484 into the expanding outer chambers 42b. Fluids from collapsing chambers 42b and 44b are discharged through kidney ports 486 and 484 into channel 4718 where they mix and flow out through fluid port 482. By utilizing appropriate valves and switches (not shown) at the source of the fluids, a plurality of different fluids, or a single kind of fluid (such as plain rinse water) may alternately be selected for pumping.

Pump 450 may be converted to a two-fluid pump by substituting therein end plate 455B of FIG. 28 and channel plate 472C of FIG. 25. In operation, one fluid enters port 482', passes through channel 471C, through inner kidney port 486 and into the inner expanding chambers 441). As these chambers collapse the fluid is forced into kidney port 486, through channel 471C and discharged through fluid port 482. The second fluid enters port 483', flows through channel 473' into kidney port 484 and into the expanding outer chambers 42b. As the outer chambers collapse this fluid passes into kidney port 484, through channel 473 and is discharged through port 483.

As long as there is substantially no leakage between the inner and outer sets of chambers, the just described two-fluid pump can be utilized as a rotary fluid pressure intensifier by channeling fluid under pressure to the inner and outer expanding chambers. The chambers (inner or outer) with the greater volumetric displacement will function as a fluid motor and drive the other set of chambers as a pump so that the fluid entering the latter set of chambers will be discharged under increased pressure.

It should be noted that the various above described pumps could be operated as fluid motors.

FIG. 29 shows the pump 450 mounted on an electric motor 500. Spacer nuts 502 replace the bell housing nuts on the electric motor and bolts 458 are fastened into the spacer nuts to hold the pump solidly in place, and in known manner a sleeve coupler (not shown) may be used to join shaft 462 of the pump to the shaft of the motor.

FIG. 30, which is a cross-section taken along line 30-30 of FIGS. 31-34, shows a fluid pump 550 also incorporating the rotary mechanism of FIG. 4. By appropriate modification, the pump 550 can function as a single-fluid pump, a two-fluid pump, a two-stage (compound) pump, a fluid intensifier or a mixing pump.

In the pump 550, camming element 22b is held in fixed position between the end section 554 and the porting plate 556 of FIG. 32 by bolts 458 (FIG. 31) which pass through bolt holes 460 in the appropriate plates. Next adjacent the porting plate 556 is the outlet manifold 572 of FIG. 33, which is a manifold for use in a single fluid or a two-fluid mixing, single discharge pump. Adjacent the outlet manifold is the inlet manifold 573 of FIG. 34 which is an inlet manifold for use on a single fluid pump while an alternate inlet manifold for use on either a two-stage pump, a two-fluid mixer pump with a single fluid discharge or a two-fluid pump as shown in FIG. 39. End plate 555, as shown in FIG. 31, is adjacent the inlet manifold.

To operate the pump 550 as a single fluid pump it is assembled as just described but only ports 482 and 482 of end plate 555 are open; ports 482" and 482" are plugged. Upon rotation of shaft 562, fluid from an external source enters the fluid port 482 in the end plate, passes through recess 571 of inlet manifold 573 and thence via passageways 581 and 581 of manifolds 572 and 573, respectively, to ports 586 and 586 of port plate 556 whence it enters the expanding inner and outer chambers. The fluid then is forced from the collapsing inner and outer chambers 44b and 42b through port plate 556 (FIG. 32) via ports 584 and 584 through outlet manifold 572 (FIG. 33) via passageways 575 and 575', channels 578 and 578', circular channel 577, and passageway 492, and through inlet plate 573 via passageway 492' where it is discharged from the pump through outlet port 482 of end plate 555.

To change pump 550 to a two-stage pump, one need only substitute therein outlet manifold 572A of FIG. 35 for outlet manifold 572 of FIG. 32 and add cross-over manifold 562 of FIG. 36 between port plate 556 and outlet manifold 572A. Inlet manifold 573 is replaced by inlet manifold 573A of FIG. 39.

Fluid entering this two-stage pump via port 482 passes through inlet manifold 573A (FIG. 39) via fluid passageway 492, circular channel 579, channels 591 and fluid passageways 581, then through outlet manifold 572A (FIG. 35) and cross-over manifold 562 (FIG. 36) via fluid passageways 581 and then through ports 586 of port plate 556, into the expanding outer chambers 42 of the displacement element. When the outer chambers collapse, fluid is forced into ports 584 of port plate 556, through the cross-over manifold 562 via fluid passageways 575, channels 578, circular channel 576, channels 591 and passageways 581 where it returns to the expanding inner chambers 44 via ports 586 of port plate 556. As the inner chambers collapse, fluid is forced through port plate 556 via ports 584', then through fluid passageways 575 of cross-over manifold 562, then through outlet manifold 572A via fluid passageways 575, channels 578, circular channel 577' and passageways 492', then through fluid passageway 492 of inelt manifold 573A, and discharged from outlet port 482 of end plate 555.

Referring again to FIG. 30, to provide a mixing pump for two separate flids, inlet manifold 573A of FIG. 39 replaces inlet manifold 573, and inlet manifold 573M of FIG. 38 is inserted between inlet manifold 573A and end plate 555. Port 482" of end plate 555 is not plugged. With the just described arrangement fluid is brought from an outside source to the expanding inner chambers 44b via communicating port 482", pocket 598, fluid passageways 571, fluid passageways 581, and ports 586. The second fluid is brought to expanding outer chambers 42b via port 482, passageways 492, circular channel 579, channels 591, fluid passageways 581 and ports 586, all of which are in communication. Fluid from the collapsing outer chambers 42b and inner chambers 44b is dischared, respectively, through ports 

1. A rotary mechanism comprising a first camming element and a second camming element having its inner face in contact with the outer face of the first camming element, one of the contacting pair of said faces having a cam profile of at least three identical segments, each segment including a first axially-straight, radially-circular surface connected to the adjacent first surface by a second radially-circular surface of a different radius which is tangent to the first surface and may be infinity, the other of the contacting pair of faces having at least three equally spaced rollers in oversize U-shaped sockets permitting radial movement, which sockets are connected by a surface which does not interfere with the cam profile, and the number of rollers differing by at least one from the number of cam segments, each roller being in contact with the cam profile during rotation of one camming element relative to the other when the rotary mechanism is used as a fluid pressure device.
 2. A rotary mechanism as defined in claim 1 wherein the second camming element has a cam profile of four segments, each comprising a flat surface connected to the adjacent flat surfaces by a concave surface forming a 90* arc, the first camming element has m U-shaped sockets connected by arcuate surfaces having a common center, m and n being differing integers, each at least
 3. 3. A rotary mechanism as defined in claim 1 further including a third camming element having its inner face in contact with the outer face of the second camming element to provide a second pair of contacting faces, one of said second pair of contacting faces having a cam profile of at least three identical segments, each segment including a first axially-straight, radially circular surface connected to the adjacent first surface by a second radially-circular surface of a different radius which is tangent to the first surfaces, the other of said second pair of contacting faces having at least three equally spaced rollers in oversize U-shaped sockets permitting radial movement, which sockets are connected by a surface which does not interfere with the cam profile of the second pair, the number of rollers in the second pair differing by at least one from the number of cam segments, each roller being in contact with the cam profile of the second pair during rotation of the third camming element relative to the second when the rotary mechanism is used as a fluid pressure device.
 4. A rotary mechanism as defined in claim 3 mounted in a fluid pressure device such that the axes of the first and third camming elements are common, one of the first and third elements is stationary and the axis of the second camming element orbits about said common axes.
 5. A rotary mechanism as defined in claim 3 mounted in a fluid pressure device such that each of the camming elements rotates on a fixed axis and the axis of the second camming element is intermediate the axes of the first and third camming elements.
 6. A rotary mechanism as defined in claim 1 wherein the first camming element has a cam profile of n lobes, the second camming element has m identical axially-straight radially-circular concave surfaces terminating at m U-shaped sockets, m and n being differing integers, each at least
 3. 7. A rotary mechanism as defined in claim 6 wherein said concave surfaces have a common center.
 8. A rotary mechanism as defined in claim 6 wherein the radius of each of said concave surfaces equals or slightly exceeds the radius of a said circular surface of the cam profile.
 9. A rotary mechanism as defined in claim 6 wherein the first camming element has a central opening for journaling an eccentric of a crankshaft.
 10. A rotary mechanism comprising an outer camming element, an intermediate camming element having its outer face in contact with the inner face of the outer camming element, and an inner camming element having its outer face in contact with the inner face of the intermediate camming element, said inner and outer camming elements having axes which are common when one is not rotating, one of each contacting pair of said faces having a cam profile of at least three identical segments, each including a first axially-straight radially-circular surface connected to the adjacent first surface by a second radially-circular surface of a different radius which is tangent to the first surfaces, the other of each contacting pair of faces having at least three equally spaced rollers in oversize U-shaped sockets permitting radial movement, which sockets are connected by a surface which does not interfere with the adjacent cam profile, the number of rollers differing by one from the number of cam segments in each contacting pair of faces, and the number of cam segments and rollers at one contacting pair of faces being independent of the numbers of cam segments and rollers at the other contacting pair, and each roller being in contact with the cam profile in the contacting face during rotation of the camming elements relative to each other when the rotary mechanism is used as a fluid pressure device.
 11. In a fluid motor or pump having at least one inlet, at least one outlet and a three-element rotary displacement mechanism comprising inner and outer elements having a common fixed axis and an intermediate element, the radially outer face of the inner element, the radially inner face of the outer element, and the radially inner and outer faces of the intermediate element each having a face profile of at least three segments which cooperate to form inner and outer expanding and collapsing chambers upon rotation of the intermediate and one other of the three elements, the improvement comprising: one or two inboard plates are arranged to turn with the intermediate element at one or both of its sides, respectively, an outboard plate is attached to the outer element adjacent each inboard plate, each inboard plate has one outer port beyond the minimum radius of each segment of the outer face of the intermediate element and one inner port within the maximum radius of each segment of the inner face of the intermediate element, said outboard plate or plates have two ports aligned with and angularly offset slightly to either side of each port of the inboard plate or plates when said port of the inboard plate is centered on a fully expanded chamber, and where there are two outboard plates, each has one of said two ports which are all angularly offset to the same side, the ports of the outboard plate or plates which are offset to one side are channeled either to a single inlet or in inner and outer sets to a pair of inlets, and the ports of the outboard plate or plates which are offset to the other side are likewise channeled to one or two outlets.
 12. In a fluid motor or pump as defined in claim 11 having a single inlet and a single outlet for operation with a single fluid, the further improvement comprising: the inner, intermediate and outer units are formed to cause an inner and an outer chamber to become fully expanded simultaneously while 180* out of phase and the ports allow fluid to flow from the inlet simultaneously to each pair of expanding chambers and simultaneously from each pair of collapsing chambers to the outlet.
 13. In a fluid motor or pump as defined in claim 11 having two pairs of inlets and outlets, the further improvement comprising: the outer ports of the inboard and outboard plates communicate only to one pair of the inlet and outlets and the inner ports communicate only to the other pair of inlets and outlets to permit operation with two independent fluids.
 14. In a fluid motor or pump as defined in claim 11, the further improvement comprising: a single inboard plate, a single outboard plate has two ports angularly offset slightly to either side of each port of the inboard plate when said port of the inboard plate is centered on a fully expanded chamber, the ports of the outboard plate which are thus offset to one side are channeled either to a single inlet or in inner and outer sets to a pair of inlets, and the other ports of the outboard plate are likewise channeled to one or two outlets.
 15. In a fluid motor or pump as defined in claim 12, the further improvement comprising: an inboard plate is adjacent each side of the intermediate element, each outboard plate has one port angularly offset slightly from each port of the adjacent inboard plate when said port of the inboard plate is centered on a fully expanded chamber, all ports of one outboard plate being thus angularly offset to one side and all ports of the other outboard plate being thus angularly offset to the other side.
 16. In a fluid pump as defined in claim 15, the further improvement comprising: all outer and inner ports of one outboard plate are channeled respectively to two different inlets and all outer and inner ports of the other outboard plate are channeled to a single outlet to permit mixing of two fluids. 